This project involves the study of the physiological organization of neurons of the visual system of primates. We have examined the functional mapping on the striate cortex of the innervation density mediated by the two major classes of ganglion cells that respectively project to the parvocellular and magnocellular layers of the lateral geniculate nucleus. We have found that the mannification in striate cortex is proportional to the afferent density of one cell type, and that the so-called point-image area of striate cortex follows the reciprocal of the afferent density of the other cell type. These differences between neural maps are likely to have psychophysical consequences. In addition, an electrophysiological survey of the variation of receptive-field size with eccentricity is in progress, and we have begun preliminary recordings in striate and extrastriate cortex to examine chromatic cell properties. Finally, we are completing analyses of previous studies for their publication.